Research And Design Of CMMB Mobile TV Receiving System Under Embedded Linux

Nowadays, with the rapid improvement of multimedia communication technology, peoplecan access to various information in much more different ways. And the development of scienceand technology and the boom of the cultural media industry help to rise and expand brand-newmedia industries of new terminals and new applications continuously. CMMB is short for ChinaMobile Multimedia Broadcasting. It is a new technology of our national proprietary intellectualproperty rights mainly developed by State Administration of Radio Film and Television. It is alsoone of important platforms that the radio networks participate in the combination of threenetworks (i.e. a telecommunication network, a broadcasting and television network and Internet).Currently, CMMB mobile TV terminal are mainly based on some commercial operating systems,such as WinCE, Symbian and so on, but very few adopt the open-source Linux system, and thereare also few research papers in the embedded Linux with CMMB, it didn’t like the DVB (DigitalVideo Broadcasting) devices which have a well Linux device driver. Under the environment ofmobile multimedia broadcasting technology has been widely used, this paper aims to expositionand research CMMB receiving system key technology, receive and process of CMMB datas onembedded Linux. This has a certain reference value for CMMB terminal with embedded Linux.This paper is based on detailed analysis of the CMMB standards and receiving technology,build the receiving system’s hardware and software solution, and use modular form to completethe design and implementation of a receiving system according to the flow of data. The specificstudy and designs are as follows:(1) First of all, discussed of the CMMB standard‘s related protocols and technologies, thena overall research program of the CMMB receiving system in this paper is presented inaccordance with the theory of the mobile TV system.(2) Analysis of the key technologies of the receiver front-end system, Study the theory ofthe CMMB conditional access system. The design and implementation of CMMB receiver cardmodule are detailed description, and give a method to achieve CMMB stream descrambling. Thehard descramble used in this paper with the software can make the encryption program into clean stream, achieve the conditions receive function.(3) Research and design of CMMB receiver chip drivers and application on the embeddedLinux platform. This paper uses the method of character device driver under Linux2.6kernel todesign the SPI and receiving chips’ diver on S3C6410, the application layer control and receivethe CMMB data through the driver based on slot technology and output the MFS stream to theback-end systems.(4) According to the CMMB related protocol standard, this paper has a detailed analysisand parsing to multiplexing frame organizational structure, and accomplishes the softwarede-multiplex of multiplexing frame data on the embedded Linux. By de-multiplexing the twomodes multiplexing frames to obtain and package the audio and video data of TV broadcastingservices. Research the decoding of CMMB audio and video stream on the platform. The videostream of H.264format decoding takes advantage of Multi-Format Codec module which is inS3C6410processor, improves the decoding efficiency compared to the soft decoder. The audiodata of AAC format use of package format transform, provided directly to the soft decoderdecoding.Finally, this paper takes the S3C6410development board and CMMB receiver module asthe hardware platform, Transplant embedded Linux operation system as the software platform.Receive and de-multiplex the data of CMMB are realized after experimental debugging, and TVprograms are decoded and broadcasted on this platform in the end, the debugging results verifythe correctness of this receiving system.